Laminar flow film developing apparatus



Feb/"18, 1969 R.D.KN1GHT ET A1. 3,427,949

LAMINAR FLOW FILM DEVELOPING APPARATUS Filed April 2. 1966 ATTORNEY United States Patent O 3 Claims ABSTRACT OF THE DISCLOSURE A development apparatus used in the development of a silver halide film chip. Liquid introduced in the lower portion of the chamber will flow in a laminar manner on both sides of the film chip from the lower portion of the chamber up and out of the upper portion of the chamber into an overflow trough contacting the entire lm area to be developed. Due to the laminar flow of liquid within the chamber a sharp interface between solutions is achieved so that the various solutions can be sequentially introduced with a following solution sweeping a prior solution out of the top of the chamber into the overflow. The laminar flow provides a sharp, distinct interface with a yminimum amount of mixing of solutions.

This invention relates to film developing devices in general and more particularly to a film developing device wherein a film to be developed is restrained in a minimum volume vertically oriented development chamber and the various solutions sequentially pumped into the lower portion of the development chamber to provide a laminar flow of the solutions in an upward direction over the film surface before flowing out the top of the development chamber.

Several types of prior art developer systems have evolved. One type of system is used in the development of reel type or roll type films. In such a system, the film is passed sequentially through vats containing the requisite solutions. This process is referred to as batch or tank processing. Through use of tank processing, several benefcial effects are achieved. First, both sides of the film to be developed are contacted by the solutions. This is often necessary since in many applications gel, which must be contacted by the solutions, is deposited on the rear of the film to prevent curl. Tank processing additionally provides uniformity of application. Tank processing does, however, have certain shortcomings. Often, the concentration of chemicals is not consistent from batch to batch since there is a depletion of developing agent in the chemicals and additional contamination through the formation of `bromide ions during processing. Thus, exact uniformity of development between areas widely separated in time cannot be achieved. Additionally, when silver film is being developed, colloidal silver particles are formed. While the depletion of chemicals and formation of colloidal silver particles may not be critical in the usual reel film type situ-ation, in applications where uniformity of develop- ,ment is highly critical and where silver particles cannot be tolerated as in micro coded storage systems, this type processing is not satisfactory.

Recently, applications have evolved where a single film chip must be developed. In one such application, the aperture of a conventional aperture card is developed while in another, film chips upon which binary encoded data is recorded, must be developed. In the aperture card application, the development method employed is to seal a chamber around the aperture and sequentially spray the various developer solutions, eg., developer, stop, rinse, etc. on the emulsion surface. This spray or agitation method works well where uniformity of development is not critical ICC from aperture to aperture or where variations in development on the aperture itself can be tolerated. However, where uniformity of development across an aperture and/ or uniformity of development from aperture to aperture is necessary, spray type developers are unsatisfactory. Likewise, where anti-halation backing is present or where a gel is placed on the back side of the film to prevent curl, spray development is unsatisfactory since only the emulsion side of the film is contacted by the solutions.

Ideally, then, a development device for and method of developing film chips should provide uniform development across the image area of the film chip as well as uniform development from film chip to film chip. Likewise, the benefits of tank processing wherein uniformity of application is provided as well as development of both sides of the fil-m chip is desirable while the above recited shortcomings of tank processing systems such as the depletion of chemical problems and the formation of colloidal silver should be prevented.

It is therefore an object of the present invention to provide a novel development method.

It is another object of the present invention to provide a new development apparatus for developing a film strip or chip.

Another object of the present invention is to provide a novel development method wherein development solutions are caused to flow in a laminar manner over the surface of a film to be developed.

Another object of the present invention is to provide a novel development method wherein development solutions are caused to flow in a laminar manner past a film to be developed and the solutions caused to contact each area of each film chip an equal amount of time to provide uniformity of development of each individual film chip as well as uniformity of development from film chip to film chip.

Another object of the present invention is to provide a novel development device wherein development solutions are entered into the lower portion of a small volume development chamber and caused to flow in a laminar manner across the film chip to be developed and out the top of the development chamber.

Other and further objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings in which:

FIG. l is an isometric view of the development device showing the fluid passages or channels of the device as well as a film chip to be developed restrained in the development chamber;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a cutaway frontal view of the development device taken along lines 3 3 of FIG. 2 and FIG. 4 is a cutaway side view taken along lines 4 4 of FIG. 2.

Briefly, a novel development method and apparatus is provided wherein solutions used in the development of, for instance, a silver halide film chip, `are caused to sequentially flow on both sides past the film chip. The film chip is restrained in a development chamber of a size such that liquid introduced in the lower portion of the chamber by means of fluid passages will flow in a laminar manner on both sides of the film chip from the lower portion of the chamber up and out of the upper portion of the chamber into an overflow trough thereby contacting the entire film area to be developed. The fluid is then drained out of the overflow trough by means of fluid passages and disposed of. Due to the laminar flow of liquid within the chamber, a sharp interface between solutions is achieved so that the various solutions `can be sequentially introduced with a following solution sweeping a prior solution out of the top of the chamber into the overflow. The

laminar iiow provides this sharp, distinct interface with a minimum amount of mixing of solutions.

Refer first to FIG. wherein is shown an isometric View of a novel development device suitable for use in the subject novel development process. As shown, the `development device generally designated at 1 includes a thin substantially vertically oriented elongated development chamber 2 in which is suspended or restrained a chip 3 to be developed. The chip 3 has picker openings `4 and 5 which are used by an associated picker mechanism, not shown, for insertion and removal of the chip 3.

As better shown in FIG. 2 the chip 3 is held from contact with the side walls 6 and 7 of the development cham'- ber by means of the restraining V grooves 8 and 9 formed by the end Walls of the development chamber 2. Additionally, as shown in FIG. 2, the walls 6 and 7 are closely spaced from the restrained chip 3 such that upon introduction of liquid, as will hereinafter be described, a laminar flow of the liquid past the chip 3 is achieved. While developing devices having a .O35 inch spacing be- V'tween the chip and side walls have been successfully operated, to minimize usage of solutions the spacing and 'consequent development chamber volume should ideally be less; however, the smaller the spacing the greater the tendency toward 'bubble entrapment. It has been found that a good trade-off from the standpoint of minimum solution usage versus the problem of bubble entrapment is provided with a wall chip spacing of .010 inch.

Referring again to FIG. l, an overflow trough 10 which is connected by means of a cylindrical overliow channel 11 is connected to an outlet chamber 12. The overfiow Ifrom the outlet chamber 12 may be taken by, for example, the pluggable outlet pipe 13.

I As further shown in FIG. 1, a pluggable inlet pipe 14 is inserted into the inlet chamber 15 which is, in turn, connected to dispensing channel 16 which, in turn, is connected by means of dispensing subchannels 17-20 to a lower chamber opening or bottom dispersion chamber 21. The chip 3 in the development chamber 2 is supported off the floor of the lower dispersion chamber 21 by three feet 22-24. Thus, iiuid entering through the dispensing subchannels 17-20 can flow through the dispersion chamber 21 and up both sides of the chip 3. FIG. 3 shows more clearly the support of lthe chip 3 by means of feet 22-24. In FIG. 4, which is a cutaway side view taken along 'lines 4-4 of FIG. 2, the elongated development chamber and the proximity of the walls 6 and 7 to the chip 3 is shown. Thus, the walls 6 and 7 are parallel.

In operation, the solutions are introduced sequentially into the dispensing channel 16 through the inlet chamber 15. The fiuids then flow down through the dispensing subchannels 1720 into the lower dispersion chamber 21. Continued application of fluid to the dispersion chamber causes the fluid to flow up past both sides of the chip 3. When the development chamber 2 is completely filled, the vfluid will overow through the upper channel opening defined by the development chamber wall 7 and chip and the development chamber Wall 6 and chip through picker ,openings 4 and 5 of the chip. The fluids are taken from the overow trough 10 through the cylindrical overflow channel 11 and outlet chamber 12. In normal development, the first solution introduced is the developer. As previously discussed in many applications, it is extremely important that the developing solution contact each area of the emulsion of the chip for an equal time .and that the time of contact be controllable within very well defined limits such that chip to chip delvelopment can be made uniform. This uniformity of ap- I'plication and exact control over the amount of time that 'the emulsion is exposed to the developer fluid can be provided through use of the subject method and device.

At a predetermined time, the fluid which is to follow the previous fluid, as stop would follow developer, is introduced through the inlet chamber 15. The introduction of this fluid will cause it to then ow down into the lower dispersion chamber 21 and tiow in a laminar manner up through the development chamber 2 thus forcing the de veloper out of the development chamber and into the overflow trough 10. Since a laminar fiow is provided, there is a sharp interface such that there is very little mixing of the stop and developer at the interface so that a clean sweep of the developer from the face of the film is achieved. It should be obvious that if the rate of tiow of the incoming developer and the rate of ow of the incoming stop is equal, that the developer will contact all parts of the film emulsion for an equal amount of time since the portion of the film chip which is first contacted by the developer is the portion of the film chip which is first contacted by the stop. This would not be the case if the developer were drained out of the bottom of the developer device.

In a developing operation, the remaining solutions are then sequentially caused to pass into the lower portion of the development chamber as above described and up through it and out of the overfiow trough 10, channel 11 and chamber 12.

As will be obvious, it is important that the development chamber reside in a substantially vertical position. By a substantially vertical position is meant that the chamber must be positioned so that as the solutions move from the bottom of the chamber upward that the film be contacted by the solutions. This would not be the case, of course, if the chamber is lying fiat on its sides or nearly flat. Likewise, as will be apparent, it is important that the line of overow from the development chamber as viewed in FIG. 3 be substantially horizontal. Otherwise, a good sweep of the solutions from the development would not be provided.

While in the embodiment shown and described, an overflow trough is used to accommodate the used solutions, there are many other Ways of collecting the used solutions. For instance, the upper portion of the development chamber could be directly sealed to an overflow outlet. The main criterion is that the solutions ow through a substantially vertically oriented development from the bottom to top in a substantially laminar manner.

In summary a novel developing method and apparatus Lis provided wherein solutions used in the development of, for instance, a silver halide film chip, are caused to sequentially flow on both sides of a film chip 3 to be developed. The film chip 3 is restrained by V grooves 8 .and 9 in a development chamber 2 of a size such that a liquid introduced at the lower portion of the chamber by means of fluid passages 16-20 will ow in a laminar manner on both sides of the chip from the lower dispersion chamber 21 up and out of the upper portion of the chamber 2 thereby contacting the entire area to be developed. The uid is then taken from an overflow trough 10 by means of iiuid passages 11 and 12 and disposed of. Due to the laminar flow of the liquid within the chamber 2, the various solutions can be sequentially introduced with a following solution causing the previous solution to be forced out through the upper portion of the development chamber 2 into the overtiow trough 10. The laminar flow provides an effective sharp interface with a minimum amount of mixing of solutions.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the .art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. An apparatus for contacing an area of a substantially at member sequentially with a first and then a second solution, said apparatus comprising:

a substantially vertically oriented chamber defined by a pair of sidewalls and endwalls and including upper and lower openings;

said endwalls including means for restraining said arca of said member in said chamber out of contact with either of `said sidewalls and the spacing between said area and said sidewalls is such that said'solutions flow in a laminar manner over said area, overow means connected to said upper opening; and means for sequentially introducing said rst solution nto said lower openin g to cause said solution to 110W up into said chamber and then said second solution to sweep said first solution out of said chamber through said upper opening. 2. The .apparatus of claim 1 wherein said sidewalls are substantially parallel.

are positioned from said area of said member by a spacing of between .010 inch and .035 inch.

NORTON ANSHER,

References Cited Primary Examiner.

CHARLES E. SMITH, Assistant Examiner.

3. The apparatus of claim 2 wherein said sidewalls 15 95 96 U.S. Cl. X.R. 

